1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17package android.support.design.widget;
18
19import android.graphics.Rect;
20import android.os.Build;
21import android.view.View;
22import android.view.ViewGroup;
23
24class ViewGroupUtils {
25
26    private interface ViewGroupUtilsImpl {
27        void offsetDescendantRect(ViewGroup parent, View child, Rect rect);
28    }
29
30    private static class ViewGroupUtilsImplBase implements ViewGroupUtilsImpl {
31        @Override
32        public void offsetDescendantRect(ViewGroup parent, View child, Rect rect) {
33            parent.offsetDescendantRectToMyCoords(child, rect);
34            // View#offsetDescendantRectToMyCoords includes scroll offsets of the last child.
35            // We need to reverse it here so that we get the rect of the view itself rather
36            // than its content.
37            rect.offset(child.getScrollX(), child.getScrollY());
38        }
39    }
40
41    private static class ViewGroupUtilsImplHoneycomb implements ViewGroupUtilsImpl {
42        @Override
43        public void offsetDescendantRect(ViewGroup parent, View child, Rect rect) {
44            ViewGroupUtilsHoneycomb.offsetDescendantRect(parent, child, rect);
45        }
46    }
47
48    private static final ViewGroupUtilsImpl IMPL;
49
50    static {
51        final int version = Build.VERSION.SDK_INT;
52        if (version >= 11) {
53            IMPL = new ViewGroupUtilsImplHoneycomb();
54        } else {
55            IMPL = new ViewGroupUtilsImplBase();
56        }
57    }
58
59    /**
60     * This is a port of the common
61     * {@link ViewGroup#offsetDescendantRectToMyCoords(android.view.View, android.graphics.Rect)}
62     * from the framework, but adapted to take transformations into account. The result
63     * will be the bounding rect of the real transformed rect.
64     *
65     * @param descendant view defining the original coordinate system of rect
66     * @param rect (in/out) the rect to offset from descendant to this view's coordinate system
67     */
68    static void offsetDescendantRect(ViewGroup parent, View descendant, Rect rect) {
69        IMPL.offsetDescendantRect(parent, descendant, rect);
70    }
71
72    /**
73     * Retrieve the transformed bounding rect of an arbitrary descendant view.
74     * This does not need to be a direct child.
75     *
76     * @param descendant descendant view to reference
77     * @param out rect to set to the bounds of the descendant view
78     */
79    static void getDescendantRect(ViewGroup parent, View descendant, Rect out) {
80        out.set(0, 0, descendant.getWidth(), descendant.getHeight());
81        offsetDescendantRect(parent, descendant, out);
82    }
83
84}
85